Use dex cache from compilation unit in RTP.

Avoid calling the costly ClassLinker::FindDexCache() from
reference type propagation when the dex cache from the
compilation unit will do, i.e. almost always. Compiling
the Nexus 5 boot image on host under perf(1) shows that
the FindDexCache() hits drop from about 0.2% to almost
nothing, though enabling inlining for the boot image will
increase it a bit to 0.03% due to unavoidable calls from
the inliner.

Also clean up the ScopedObjectAccess usage a bit.

Change-Id: I426a5f9f5da9e64fad2ea57654240789a48d3871

1 files changed, 22 insertions, 6 deletions

diff --git a/compiler/optimizing/inliner.cc b/compiler/optimizing/inliner.cc
index 77e0cbc600..d60298b954 100644
--- a/compiler/optimizing/inliner.cc
+++ b/compiler/optimizing/inliner.cc
@@ -411,7 +411,10 @@ bool HInliner::TryInlineMonomorphicCall(HInvoke* invoke_instruction,
 
   // Run type propagation to get the guard typed, and eventually propagate the
   // type of the receiver.
-  ReferenceTypePropagation rtp_fixup(graph_, handles_, /* is_first_run */ false);
+  ReferenceTypePropagation rtp_fixup(graph_,
+                                     outer_compilation_unit_.GetDexCache(),
+                                     handles_,
+                                     /* is_first_run */ false);
   rtp_fixup.Run();
 
   MaybeRecordStat(kInlinedMonomorphicCall);
@@ -532,7 +535,10 @@ bool HInliner::TryInlinePolymorphicCall(HInvoke* invoke_instruction,
   MaybeRecordStat(kInlinedPolymorphicCall);
 
   // Run type propagation to get the guards typed.
-  ReferenceTypePropagation rtp_fixup(graph_, handles_, /* is_first_run */ false);
+  ReferenceTypePropagation rtp_fixup(graph_,
+                                     outer_compilation_unit_.GetDexCache(),
+                                     handles_,
+                                     /* is_first_run */ false);
   rtp_fixup.Run();
   return true;
 }
@@ -709,7 +715,10 @@ bool HInliner::TryInlinePolymorphicCallToSameTarget(HInvoke* invoke_instruction,
   deoptimize->CopyEnvironmentFrom(invoke_instruction->GetEnvironment());
 
   // Run type propagation to get the guard typed.
-  ReferenceTypePropagation rtp_fixup(graph_, handles_, /* is_first_run */ false);
+  ReferenceTypePropagation rtp_fixup(graph_,
+                                     outer_compilation_unit_.GetDexCache(),
+                                     handles_,
+                                     /* is_first_run */ false);
   rtp_fixup.Run();
 
   MaybeRecordStat(kInlinedPolymorphicCall);
@@ -971,7 +980,8 @@ HInstanceFieldGet* HInliner::CreateInstanceFieldGet(Handle<mirror::DexCache> dex
       // dex pc for the associated stack map. 0 is bogus but valid. Bug: 26854537.
       /* dex_pc */ 0);
   if (iget->GetType() == Primitive::kPrimNot) {
-    ReferenceTypePropagation rtp(graph_, handles_, /* is_first_run */ false);
+    // Use the same dex_cache that we used for field lookup as the hint_dex_cache.
+    ReferenceTypePropagation rtp(graph_, dex_cache, handles_, /* is_first_run */ false);
     rtp.Visit(iget);
   }
   return iget;
@@ -1319,13 +1329,19 @@ void HInliner::FixUpReturnReferenceType(HInvoke* invoke_instruction,
         if (invoke_rti.IsStrictSupertypeOf(return_rti)
             || (return_rti.IsExact() && !invoke_rti.IsExact())
             || !return_replacement->CanBeNull()) {
-          ReferenceTypePropagation(graph_, handles_, /* is_first_run */ false).Run();
+          ReferenceTypePropagation(graph_,
+                                   outer_compilation_unit_.GetDexCache(),
+                                   handles_,
+                                   /* is_first_run */ false).Run();
         }
       }
     } else if (return_replacement->IsInstanceOf()) {
       if (do_rtp) {
         // Inlining InstanceOf into an If may put a tighter bound on reference types.
-        ReferenceTypePropagation(graph_, handles_, /* is_first_run */ false).Run();
+        ReferenceTypePropagation(graph_,
+                                 outer_compilation_unit_.GetDexCache(),
+                                 handles_,
+                                 /* is_first_run */ false).Run();
       }
     }
   }